Nestled among the colorful stalls of Thai fresh markets, few fruits are as beloved or as culturally significant as the green-skinned citrus known locally as ส้มเขียวหวาน (som kiao wan), or more widely as the tangerine or mandarin orange. While its sweet, juicy flesh is a popular snack across Thailand, it’s the sun-dried peel—often overlooked in the West—that has woven itself into the fabric of both culinary and traditional medicinal practices in Thai society. Today, as scientific research probes the ancient wisdom of herbal remedies, the humble tangerine peel emerges as a fascinating protagonist at the intersection of culture, nutrition, and pharmacology.
For centuries, Thai traditional medicine has tapped into the diverse uses of tangerine peel. Local healers incorporate it in remedies said to balance digestion, relieve coughs, reduce phlegm, and stimulate appetite. These practices echo across Asia: in Chinese herbalism, aged tangerine peel (chenpi) is prized for its ability to harmonize the spleen and stomach, while in Vietnamese households, it is a mainstay in wintertime broths and teas. In northern Thai dialects, names like มะขุน, มะเขียว, and ส้มจุก reflect the tangerine’s regional adaptation and enduring appeal. Beyond the kitchen and clinic, dried tangerine peel finds its way into ancestral offerings and New Year celebrations, symbolizing prosperity and renewal.
But why does this aromatic rind enjoy such a venerable status? The answer begins with its deep-rooted cultural context. In Thailand, fermented or sun-dried tangerine peel is a staple for treating minor digestive upset, particularly after heavy or oily meals—a nod to its slightly bitter, aromatic quality that is thought to ‘cut’ greasiness and restore internal balance. Recipes shared across generations involve boiling the peel to extract its essence, either alone or combined with ingredients like ginger and licorice root, producing teas or decoctions for mild colds or coughs. In some communities, the peel is candied and eaten as a treat, hinting at both its flavor and perceived health-promoting properties (thewoksoflife.com).
Modern researchers now turn a scientific lens on this traditional wisdom. As it turns out, tangerine (Citrus reticulata) peel is a veritable treasure trove of phytochemicals. The dried rind contains potent flavonoids, polymethoxyflavones, essential oils like D-limonene, and a range of phenolic compounds—all of which have drawn interest for their antioxidant, anti-inflammatory, and digestive-supporting effects (pubmed.ncbi.nlm.nih.gov/36558081/).
One study evaluated the skin anti-aging potential of alcoholic extracts from Citrus reticulata peel by employing multiple in vitro assays. The researchers found that a hot alcoholic extract of tangerine peel (using Soxhlet extraction) exhibited significantly higher phenolic and flavonoid content—and, in turn, stronger antioxidant activity—compared to a cold extract. Antioxidant activity was measured through radical scavenging assays such as DPPH and ABTS, where the tangerine peel extract showed impressive effectiveness. Notably, this extract also demonstrated significant inhibition of collagenase and elastase enzymes, which are closely linked to skin aging and wrinkle formation. The implication: tangerine peel may offer promise for anti-wrinkle skincare formulations, harnessing nature’s biochemistry to maintain youthful skin (PMC4908842).
Beyond skin health, Citrus reticulata’s chemical richness extends into broader preventive and therapeutic domains. Flavonoids isolated from the peel—such as nobiletin, tangeretin, and hesperidin—have demonstrated antioxidant activity that helps neutralize harmful free radicals. These natural compounds contribute to lowering oxidative stress, a process implicated in chronic diseases ranging from cardiovascular disease to neurodegenerative disorders (frontiersin.org, MDPI). A recent systematic analysis of flavonoids in citrus peels confirmed their potent anti-inflammatory and antioxidant properties, suggesting that regular dietary inclusion could benefit overall cellular health (ScienceDirect).
But does scientific validation extend to clinical settings? A recent randomized, placebo-controlled clinical trial explored the potential cognitive benefits of Citrus peel extract supplementation in adults experiencing subjective cognitive decline (a risk factor for dementia). Over 36 weeks of daily supplementation, the trial found no significant difference in cognitive outcomes between those receiving tangerine peel extract and a placebo group (PubMed). While these results may temper overly optimistic expectations, they also highlight the importance of grounding health claims in robust clinical evidence rather than tradition alone.
Even so, the broad pharmacological canvas of Citrus reticulata peel continues to intrigue scientists. Laboratory studies suggest the extract’s capacity to modulate immune responses, mitigate oxidative liver stress, and even suppress viral entry in cell cultures—particularly due to components like hesperidin (Biorxiv). These findings complement its storied use in respiratory ailments. In both Thai and Chinese folk medicine, decoctions or powders of dried tangerine peel remain popular as natural cough suppressants and expectorants, purportedly thinning mucus and easing chest congestion during seasonal illnesses.
From a nutritional perspective, consuming tangerine peel is not without precedent. In Chinese kitchens, dried tangerine peel (chenpi) is prized not only for its aroma in savory dishes, but also for its potential healthful properties, which are thought to improve with age. Thai cooks use grated peel—fresh or dried—to add zest to cakes, desserts, and infusions. Urban home cooks sometimes prepare their own, drying washed peels in the sun and storing them in glass jars for use year-round (thewoksoflife.com). A similar tradition exists in Northern Thailand, where candied peels are shared during festivals.
Yet, with opportunity comes caution. The pharmacologically active compounds in tangerine peel can interact with medications, particularly those processed by liver enzymes (such as statins and some antidepressants). Essential oils, while antimicrobial and fragrant, may cause skin irritation in sensitive individuals. Excessive or unsupervised consumption, especially of processed or pesticide-laden peels, could introduce harmful residues. Traditional practitioners and modern herbalists alike counsel moderation and care: Always consult a licensed health professional before incorporating tangerine peel or other potent botanicals into regular use, especially for young children, pregnant women, or those with chronic medical conditions.
In Thailand’s rapidly evolving health landscape, the story of Citrus reticulata peel mirrors broader societal trends: a rekindled interest in plant-based remedies, a drive to scientifically validate local knowledge, and a burgeoning market for natural health products. Thai universities are involved in screening locally grown citrus varieties for their antioxidant potency and exploring their integration into functional foods—such as teas, supplements, and even skincare lines. For Thai readers, the practical takeaway is both empowering and measured: dried tangerine peel, when properly sourced and prepared, can enhance food, flavor, and possibly wellness, but it is not a substitute for medical care.
As research deepens our understanding of this treasured rind, Thai households need not abandon the wisdom of their ancestors. Rather, blending the best of both worlds—time-honored practices and rigorous scientific scrutiny—offers a model for holistic self-care that honors tradition and prioritizes safety. For cooks, herbalists, and wellness seekers alike, the versatile tangerine peel is more than a relic of the past: it is a fragrant link between heritage and health, resilience, and renewal.
Thai readers curious to explore tangerine peel in their own lives are advised to:
- Use only untreated, organically grown peels to avoid chemical residues.
- Start with culinary doses, such as zesting or adding small pieces to tea or soup.
- Watch for allergic reactions and discontinue use if any irritation occurs.
- For medicinal doses or conditions, consult a healthcare professional—preferably one familiar with traditional Thai medicine.
This article is for educational purposes only and not intended to replace medical advice. When considering herbal remedies, especially those with potent bioactive compounds, personal safety and professional guidance should always come first.
Sources: Dried Mandarin Orange Peel: Chinese Ingredients – The Woks of Life | Valorization of Citrus Reticulata Peels for Flavonoids and Antioxidant Activity | Citrus supplementation in subjective cognitive decline: results of a 36-week, randomized, placebo-controlled trial | Evaluation of Skin Anti-aging Potential of Citrus reticulata Blanco Peel | Citrus Peel Flavonoid Extracts: Health-Beneficial Bioactivities and Mechanisms | An Overview of Bioactive Flavonoids from Citrus Fruits - MDPI